for this, i'm going to ask first and drill after. i don't want to have to replace things i've accidentaly drilled holes through.
i want to drill a good size (1/2") hole through the firewall as far left and high uop as i can from the inside out on a gmc sprint (el camino, same difference). i've got a spot picked out just left of the fuse box and it appears clear from the inside and out. is there anything in the spot essentially ontop of wheer the parking break pedal is that i should know about before i drill a hole there?
thanks fellas.

Please state the year model it might make a difference i am sure someone here knows.

i want to drill a good size (1/2") hole through the firewall as far left and high uop as i can from the inside out on a gmc sprint (el camino, same difference). i've got a spot picked out just left of the fuse box and it appears clear from the inside and out.

If the spot you picked out is clear inside and out, then it is a pretty safe location to drill. Make sure you use a grommet if you plan to run electric cables, so that over time the metal will not wear down the insulation on the wire(s) and cause a short.

mission accomplished. thanks fellas!